Well, it's too late, but I would have suggested the leg locks. As a hobbyist Judoka who would be hoping for something straightforward I could take away from a 2 hour seminar (and that wouldn't just be a repeat of what I'm doing anyway) leglocks would have been cool. Plus it would have made for a cool "intro to Sambo" type deal for you since leglocks are (supposedly) Sambo's speciality.